Identification and utilisation of quantitative trait loci to improve terminal drought tolerance in pearl millet (Pennisetum glaucum (L.) R.Br.)

摘要

Drought at the reproductive stage of pearl millet is one of the most important environmental factors reducing its yield and yield stability. We are using a QTL mapping approach to better understand the genetic and physiological basis of drought tolerance in this crop and to devise strategies to utilise the identified QTLs for improving drought tolerance and yield in water-Limited environments. Test-crosses of two sets of mapping population progenies, derived from inbred pollinators and from seed parents differing in their response to drought, were evaluated in a range of managed terminal drought-stress environments to identify individual QTLs associated with drought tolerance. A number of QTLs associated with drought tolerance of grain yield and its agronomic and physiological components were identified. Some of the identified QTLs were common across water-stress environments and genetic backgrounds of the two mapping populations while others were specific to a particular water-stress environment or genetic background. Interestingly, all the identified QTLs contributed to increased drought tolerance either throught their effect on increased maintenance of growth, or harvest- index, or both in terminal drought-stress environments. Marker-assisted backcross transfer of the identified QTLs into the elite parent of these mapping populations and their further use in the improvement of pearl millet productivity in water-limited environments is discussed.